Carolyn Wells 
The White Alley [EPUB ebook] 
A Fleming Stone Mystery

Guests gather for the weekend at White Birches, the upper New York mansion of millionaire scion Justin Arnold. Festivities are cut short when the host inexplicably goes missing, presumed to be hiding or unwell somewhere within the grounds of his heavily protected, fortress-like estate. With amateur sleuths and the local police unable to solve the mystery, they call in Detective Fleming Stone and what starts as a missing person thriller becomes a murder mystery in this clever locked-room puzzler from Carolyn Wells, author of 
The Clue.